---
category: Validator
created: '2020-05-16'
title: Check if a string contains lower case characters
updated: '2021-10-13'
---

**JavaScript version**

```js containsLowerCase.js
const containsLowerCase = (str) => str !== str.toUpperCase();
```

**TypeScript version**

```ts containsLowerCase.ts
const containsLowerCase = (str: string): boolean => str !== str.toUpperCase();
```

**Examples**

```js examples.js
containsLowerCase('Hello World'); // true
containsLowerCase('HELLO WORLD'); // false
```
